man/sd_bus_message_get_signature.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   5
   6 <refentry id="sd_bus_message_get_signature" xmlns:xi="http://www.w3.org/2001/XInclude">
   7   <refentryinfo>
   8     <title>sd_bus_message_get_signature</title>
   9     <productname>systemd</productname>
  10   </refentryinfo>
  11
  12   <refmeta>
  13     <refentrytitle>sd_bus_message_get_signature</refentrytitle>
  14     <manvolnum>3</manvolnum>
  15   </refmeta>
  16
  17   <refnamediv>
  18     <refname>sd_bus_message_get_signature</refname>
  19     <refname>sd_bus_message_is_empty</refname>
  20     <refname>sd_bus_message_has_signature</refname>
  21
  22     <refpurpose>Query bus message signature</refpurpose>
  23   </refnamediv>
  24
  25   <refsynopsisdiv>
  26     <funcsynopsis>
  27       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  28
  29       <funcprototype>
  30         <funcdef>const char* <function>sd_bus_message_get_signature</function></funcdef>
  31         <paramdef>sd_bus_message *<parameter>message</parameter></paramdef>
  32         <paramdef>int <parameter>complete</parameter></paramdef>
  33       </funcprototype>
  34
  35       <funcprototype>
  36         <funcdef>int <function>sd_bus_message_is_empty</function></funcdef>
  37         <paramdef>sd_bus_message *<parameter>message</parameter></paramdef>
  38       </funcprototype>
  39
  40       <funcprototype>
  41         <funcdef>int <function>sd_bus_message_has_signature</function></funcdef>
  42         <paramdef>sd_bus_message *<parameter>message</parameter></paramdef>
  43         <paramdef>const char *<parameter>signature</parameter></paramdef>
  44       </funcprototype>
  45     </funcsynopsis>
  46
  47   </refsynopsisdiv>
  48
  49   <refsect1>
  50     <title>Description</title>
  51
  52     <para><function>sd_bus_message_get_signature()</function> returns the signature of message
  53     <parameter>message</parameter>. If <parameter>complete</parameter> is true, the signature of the
  54     whole message is returned, and just the signature of the currently open container otherwise.
  55     </para>
  56
  57     <para><function>sd_bus_message_is_empty()</function> returns true if the message is empty,
  58     i.e. when its signature is empty.</para>
  59
  60     <para><function>sd_bus_message_has_signature()</function> returns true if the signature of the
  61     message <parameter>message</parameter> matches given <parameter>signature</parameter>. Parameter
  62     <parameter>signature</parameter> may be <constant>NULL</constant>, this is treated the same as
  63     an empty string, which is equivalent to calling <function>sd_bus_message_is_empty()</function>.
  64     </para>
  65 </refsect1>
  66
  67   <refsect1>
  68     <title>Return Value</title>
  69
  70     <para>On success, <function>sd_bus_message_get_signature()</function> returns
  71     the signature, and <constant>NULL</constant> on error.</para>
  72
  73     <para>The other functions return 0 or a positive integer on success. On failure, they return a
  74     negative errno-style error code.</para>
  75
  76     <refsect2>
  77       <title>Errors</title>
  78
  79       <para>Returned errors may indicate the following problems:</para>
  80
  81       <variablelist>
  82         <varlistentry>
  83           <term><constant>-EINVAL</constant></term>
  84
  85           <listitem><para>The <parameter>message</parameter> parameter is <constant>NULL</constant>.
  86           </para></listitem>
  87         </varlistentry>
  88
  89         <varlistentry>
  90           <term><constant>NULL</constant></term>
  91
  92           <listitem><para>The <parameter>message</parameter> parameter is <constant>NULL</constant>.
  93           </para></listitem>
  94         </varlistentry>
  95       </variablelist>
  96     </refsect2>
  97   </refsect1>
  98
  99   <xi:include href="libsystemd-pkgconfig.xml" />
 100
 101   <refsect1>
 102     <title>See Also</title>
 103
 104     <para>
 105       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 106       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 107       <citerefentry><refentrytitle>sd_bus_message_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 108     </para>
 109   </refsect1>
 110
 111 </refentry>